Battery systems are implemented as a power source for a wide variety of different applications. One problem is that it is difficult to accurately estimate the amount of energy remaining in a partially depleted battery. Therefore, conventional battery systems may become depleted with insufficient warning.
One known method for estimating battery life involves monitoring battery output voltage. A problem with this method is that many batteries have a voltage output curve that remains fairly flat during discharge until the battery is very close to depletion. Another problem with this method is that variables such as current load, battery age, and battery temperature can impact voltage output such that a battery life estimate based on voltage output may be imprecise.
Another known method for estimating battery life involves a technique referred to as Coulomb counting. A problem with Coulomb counting is that the battery must be periodically fully charged in order to provide a known full condition that is implemented as a reference. If the battery is not fully charged at a sufficiently frequent interval, the Coulomb counting technique can become imprecise.